Troika raises SANs' IQ

SAN Volume Suite sharpens SANs with intelligent services

By Mario Apicella

InfoWorld|Jul 25, 2005

Troika Networks may not be the first vendor that comes to mind when talking about intelligent storage networks, but it should be: It has been a pioneer in the field since the company was founded in 1998.

Throughout the years, Troika has packed into its Accelera NSS (network storage services) appliance some unique features, including resilient hardware acceleration for both FC (Fibre Channel) and I/O traffic and the ability to integrate with a variety of third-party applications such as backup, mirroring, and snapshots.

Accelera has also been certified with FC switches and storage arrays from multiple vendors, which means customers get more flexibility in choosing storage gear when they decide to add more capacity or replace aging equipment.

These advantages position the Accelera as a prime candidate for adding intelligence to your SAN. Recently, Troika started bundling its Accelera device with a powerful application suite from longtime partner StoreAge. This single, bundled offering -- the aptly named SVS (SAN Volume Suite) -- is a good move, as SVS simplifies SAN deployment and maintenance and includes powerful applications such as mirroring and snapshots.

Big brain, slim body

I reviewed SVS on a test bed in which the networking gear -- or the head of my test SAN -- far outweighed the body, which was a single, nondescript storage enclosure with 12 Seagate FC drives.

To create a resilient configuration, my test bed had two Acceleras, one with 16 FC ports and the other with eight. Both were connected with double links to fabric switches from Brocade and QLogic.

In addition, my test bed included two dedicated Windows machines running SVS's SVM (Storage Virtualization Manager) suite. As its name implies, SVM is used to control storage virtualization tasks, such as creating or expanding volumes, creating snapshots and mirrors, and making full copies of virtual volumes.

Each SVM machine hosts the virtualization metadata for your environment and shares it with the Accelera boxes. It's important to note that in a Troika SAN, you configure the FC switches to prevent a direct connection between hosts and storage devices. In fact, the Accelera-SVM combo has full control over directing and dispatching data traffic, while the FC switches assume an ancillary role as data path devices.

I used two machines to simulate applications servers -- one running VMware ESX; the other, Windows 2000. To accommodate for fail-over, each server had dual FC HBAs, obviously linked to both switches, and the Windows box had installed multipath software.

Pulling the plug

My first tests aimed at stressing the SVS's fail-over capabilities. To check how the system handled broken links, I started Iometer on that Windows server to create some traffic and to simulate a running application. I then unplugged the FC cable between the Windows server and the QLogic switch.

Each host had a double access path to the storage array, so I expected the Accelera boxes to reroute the traffic seamlessly to the other path through the second switch. It took a few seconds, but I soon saw that the lights on the Brocade switch started to blink, a clear sign that the Accelera had automatically routed the traffic previously flowing through the QLogic box. My Iometer script never had a hiccup; nor should your applications.

I reconnected the same FC cable and saw the system return automatically to its normal state, ready for other recovery procedures.

Improved resilience and active/active fail-over for your SAN are an easy sell, but Troika adds the unique and valuable twist of working with gear from different vendors. This ability allows you the rarely matched freedom to use heterogeneous storage devices and sets a clear competitive advantage over other solutions if you need to add intelligence to an existing mixed environment.

I repeated the same test several times with similar success on both the Windows and VMware servers before moving to find out how SVS reacts when losing one of its boxes. Accelera has fully redundant components, which makes show-stopping breakdowns unlikely. In fact, I had to pull both power cords to simulate a broken Accelera. This test was successful, and again SVS recovered gracefully, rerouting all the traffic to the surviving unit.

Grabbing virtual views

To complement the Accelera, Troika bundles in the SVM management suite, which offers a set of tools to carve virtual volumes for your hosts and to activate mirroring and snapshots of critical volumes.

SVM has a rather unique user interface that implements powerful features, such as creating storage pools to host homogeneous volumes, striping across multiple disks for performance, and activating fail-over.

It falls short, however, on other, perhaps less-critical features. For example, the SVM suite doesn't have an online help component, although it is needed because of the intrinsic complexity of some activities and its less-than-intuitive user dialogs.

To offset these shortcomings, SVM offers some unexpected features. On most screens, a user can activate a context search to quickly find items such as volumes or physical disks from a list. If not for the lack of help functions, this would seem like overpampering, but in this case, it's a welcome aid.

It may take some time to get used to it -- I had to look at the well-written documentation on PDF files to figure out how to do some things -- but SVM is the single GUI you will use to control all the resources of your SAN, including hosts, storage devices, and fail-over settings.

If I had to choose a single reason to recommend Troika SVS, it would be the Accelera's exceptional recovery features. Although enforcing high-availability for SANs is not unique to Troika, SVS has an edge because it works in harmony with switches and arrays from multiple vendors.

This combination makes the Troika approach a worthy alternative to monolithic, single-vendor solutions. If your SAN could use more intelligence, performance, and resilience, don't overlook the affordable and flexible SAN Volume Suite.